[Wound healing effects of silk fibroin-bone morphogenetic protein-2 scaffolds on inflammatory pulp in rats]

To identify the healing effect of electrospun silk fibroin-BMP-2 as a biologic pulp capping agent to inflammatory pulp in rat caused by lipopolysaccharide (LPS).

A total of 30 healthy adult male Wistar rats were randomly divided into five groups:(1) normal control group without operation; (2) blank control group without capping agents; (3) calcium hydroxide capping group; (4) electrospun silk fibroin capping group; (5) electrospun silk fibroin-BMP-2 capping group. Bilateral upper first molars of each rat in group 2-5 were drilled to expose the pulp to LPS which was used to establish a model of inflammatory pulp. The exposed pulp was capped with different capping agents or without capping agents. Then the hole was sealed. The animals were sacrificed on days 3, 7, and 14 post-operation and histological analysis was carried out, including HE stain and CD14 immunohistochemical stain.

On day 7 and 14, the lowest inflammatory reaction score in HE stain among pulp capping groups was that of silk fibroin-BMP-2 group. The next were calcium hydroxide group and silk fibroin group. That of blank control group was the highest. The ranking of reparative dentine scores of those groups was just reversed. The D values of immunohistochemical stain of CD14 were not significantly different in groups applied pulp capping agents but significantly lower than blank control group on days 3 and 7. However, the D value of silk fibroin-BMP-2 group (0.145±0.011) was significantly lower than blank control group (0.287±0.019), calcium hydroxide group (0.170±0.017) and silk fibroin group (0.175±0.018) on day 14.

Electrospun silk fibroin compounded with BMP-2 promoted wound healing of exposed pulp and had better potential to stimulate formation of reparative dentine to establish a suitable environment for pulp recovery.